1 /* 2 * L2TP core. 3 * 4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd 5 * 6 * This file contains some code of the original L2TPv2 pppol2tp 7 * driver, which has the following copyright: 8 * 9 * Authors: Martijn van Oosterhout <kleptog@svana.org> 10 * James Chapman (jchapman@katalix.com) 11 * Contributors: 12 * Michal Ostrowski <mostrows@speakeasy.net> 13 * Arnaldo Carvalho de Melo <acme@xconectiva.com.br> 14 * David S. Miller (davem@redhat.com) 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License version 2 as 18 * published by the Free Software Foundation. 19 */ 20 21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 22 23 #include <linux/module.h> 24 #include <linux/string.h> 25 #include <linux/list.h> 26 #include <linux/rculist.h> 27 #include <linux/uaccess.h> 28 29 #include <linux/kernel.h> 30 #include <linux/spinlock.h> 31 #include <linux/kthread.h> 32 #include <linux/sched.h> 33 #include <linux/slab.h> 34 #include <linux/errno.h> 35 #include <linux/jiffies.h> 36 37 #include <linux/netdevice.h> 38 #include <linux/net.h> 39 #include <linux/inetdevice.h> 40 #include <linux/skbuff.h> 41 #include <linux/init.h> 42 #include <linux/in.h> 43 #include <linux/ip.h> 44 #include <linux/udp.h> 45 #include <linux/l2tp.h> 46 #include <linux/hash.h> 47 #include <linux/sort.h> 48 #include <linux/file.h> 49 #include <linux/nsproxy.h> 50 #include <net/net_namespace.h> 51 #include <net/netns/generic.h> 52 #include <net/dst.h> 53 #include <net/ip.h> 54 #include <net/udp.h> 55 #include <net/udp_tunnel.h> 56 #include <net/inet_common.h> 57 #include <net/xfrm.h> 58 #include <net/protocol.h> 59 #include <net/inet6_connection_sock.h> 60 #include <net/inet_ecn.h> 61 #include <net/ip6_route.h> 62 #include <net/ip6_checksum.h> 63 64 #include <asm/byteorder.h> 65 #include <linux/atomic.h> 66 67 #include "l2tp_core.h" 68 69 #define L2TP_DRV_VERSION "V2.0" 70 71 /* L2TP header constants */ 72 #define L2TP_HDRFLAG_T 0x8000 73 #define L2TP_HDRFLAG_L 0x4000 74 #define L2TP_HDRFLAG_S 0x0800 75 #define L2TP_HDRFLAG_O 0x0200 76 #define L2TP_HDRFLAG_P 0x0100 77 78 #define L2TP_HDR_VER_MASK 0x000F 79 #define L2TP_HDR_VER_2 0x0002 80 #define L2TP_HDR_VER_3 0x0003 81 82 /* L2TPv3 default L2-specific sublayer */ 83 #define L2TP_SLFLAG_S 0x40000000 84 #define L2TP_SL_SEQ_MASK 0x00ffffff 85 86 #define L2TP_HDR_SIZE_SEQ 10 87 #define L2TP_HDR_SIZE_NOSEQ 6 88 89 /* Default trace flags */ 90 #define L2TP_DEFAULT_DEBUG_FLAGS 0 91 92 /* Private data stored for received packets in the skb. 93 */ 94 struct l2tp_skb_cb { 95 u32 ns; 96 u16 has_seq; 97 u16 length; 98 unsigned long expires; 99 }; 100 101 #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) 102 103 static atomic_t l2tp_tunnel_count; 104 static atomic_t l2tp_session_count; 105 static struct workqueue_struct *l2tp_wq; 106 107 /* per-net private data for this module */ 108 static unsigned int l2tp_net_id; 109 struct l2tp_net { 110 struct list_head l2tp_tunnel_list; 111 spinlock_t l2tp_tunnel_list_lock; 112 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2]; 113 spinlock_t l2tp_session_hlist_lock; 114 }; 115 116 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); 117 118 static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk) 119 { 120 return sk->sk_user_data; 121 } 122 123 static inline struct l2tp_net *l2tp_pernet(struct net *net) 124 { 125 BUG_ON(!net); 126 127 return net_generic(net, l2tp_net_id); 128 } 129 130 /* Tunnel reference counts. Incremented per session that is added to 131 * the tunnel. 132 */ 133 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel) 134 { 135 atomic_inc(&tunnel->ref_count); 136 } 137 138 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel) 139 { 140 if (atomic_dec_and_test(&tunnel->ref_count)) 141 l2tp_tunnel_free(tunnel); 142 } 143 #ifdef L2TP_REFCNT_DEBUG 144 #define l2tp_tunnel_inc_refcount(_t) \ 145 do { \ 146 pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \ 147 __func__, __LINE__, (_t)->name, \ 148 atomic_read(&_t->ref_count)); \ 149 l2tp_tunnel_inc_refcount_1(_t); \ 150 } while (0) 151 #define l2tp_tunnel_dec_refcount(_t) \ 152 do { \ 153 pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \ 154 __func__, __LINE__, (_t)->name, \ 155 atomic_read(&_t->ref_count)); \ 156 l2tp_tunnel_dec_refcount_1(_t); \ 157 } while (0) 158 #else 159 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t) 160 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t) 161 #endif 162 163 /* Session hash global list for L2TPv3. 164 * The session_id SHOULD be random according to RFC3931, but several 165 * L2TP implementations use incrementing session_ids. So we do a real 166 * hash on the session_id, rather than a simple bitmask. 167 */ 168 static inline struct hlist_head * 169 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id) 170 { 171 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)]; 172 173 } 174 175 /* Lookup the tunnel socket, possibly involving the fs code if the socket is 176 * owned by userspace. A struct sock returned from this function must be 177 * released using l2tp_tunnel_sock_put once you're done with it. 178 */ 179 static struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel) 180 { 181 int err = 0; 182 struct socket *sock = NULL; 183 struct sock *sk = NULL; 184 185 if (!tunnel) 186 goto out; 187 188 if (tunnel->fd >= 0) { 189 /* Socket is owned by userspace, who might be in the process 190 * of closing it. Look the socket up using the fd to ensure 191 * consistency. 192 */ 193 sock = sockfd_lookup(tunnel->fd, &err); 194 if (sock) 195 sk = sock->sk; 196 } else { 197 /* Socket is owned by kernelspace */ 198 sk = tunnel->sock; 199 sock_hold(sk); 200 } 201 202 out: 203 return sk; 204 } 205 206 /* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */ 207 static void l2tp_tunnel_sock_put(struct sock *sk) 208 { 209 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); 210 if (tunnel) { 211 if (tunnel->fd >= 0) { 212 /* Socket is owned by userspace */ 213 sockfd_put(sk->sk_socket); 214 } 215 sock_put(sk); 216 } 217 sock_put(sk); 218 } 219 220 /* Lookup a session by id in the global session list 221 */ 222 static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id) 223 { 224 struct l2tp_net *pn = l2tp_pernet(net); 225 struct hlist_head *session_list = 226 l2tp_session_id_hash_2(pn, session_id); 227 struct l2tp_session *session; 228 229 rcu_read_lock_bh(); 230 hlist_for_each_entry_rcu(session, session_list, global_hlist) { 231 if (session->session_id == session_id) { 232 rcu_read_unlock_bh(); 233 return session; 234 } 235 } 236 rcu_read_unlock_bh(); 237 238 return NULL; 239 } 240 241 /* Session hash list. 242 * The session_id SHOULD be random according to RFC2661, but several 243 * L2TP implementations (Cisco and Microsoft) use incrementing 244 * session_ids. So we do a real hash on the session_id, rather than a 245 * simple bitmask. 246 */ 247 static inline struct hlist_head * 248 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) 249 { 250 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; 251 } 252 253 /* Lookup a session by id 254 */ 255 struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id) 256 { 257 struct hlist_head *session_list; 258 struct l2tp_session *session; 259 260 /* In L2TPv3, session_ids are unique over all tunnels and we 261 * sometimes need to look them up before we know the 262 * tunnel. 263 */ 264 if (tunnel == NULL) 265 return l2tp_session_find_2(net, session_id); 266 267 session_list = l2tp_session_id_hash(tunnel, session_id); 268 read_lock_bh(&tunnel->hlist_lock); 269 hlist_for_each_entry(session, session_list, hlist) { 270 if (session->session_id == session_id) { 271 read_unlock_bh(&tunnel->hlist_lock); 272 return session; 273 } 274 } 275 read_unlock_bh(&tunnel->hlist_lock); 276 277 return NULL; 278 } 279 EXPORT_SYMBOL_GPL(l2tp_session_find); 280 281 /* Like l2tp_session_find() but takes a reference on the returned session. 282 * Optionally calls session->ref() too if do_ref is true. 283 */ 284 struct l2tp_session *l2tp_session_get(struct net *net, 285 struct l2tp_tunnel *tunnel, 286 u32 session_id, bool do_ref) 287 { 288 struct hlist_head *session_list; 289 struct l2tp_session *session; 290 291 if (!tunnel) { 292 struct l2tp_net *pn = l2tp_pernet(net); 293 294 session_list = l2tp_session_id_hash_2(pn, session_id); 295 296 rcu_read_lock_bh(); 297 hlist_for_each_entry_rcu(session, session_list, global_hlist) { 298 if (session->session_id == session_id) { 299 l2tp_session_inc_refcount(session); 300 if (do_ref && session->ref) 301 session->ref(session); 302 rcu_read_unlock_bh(); 303 304 return session; 305 } 306 } 307 rcu_read_unlock_bh(); 308 309 return NULL; 310 } 311 312 session_list = l2tp_session_id_hash(tunnel, session_id); 313 read_lock_bh(&tunnel->hlist_lock); 314 hlist_for_each_entry(session, session_list, hlist) { 315 if (session->session_id == session_id) { 316 l2tp_session_inc_refcount(session); 317 if (do_ref && session->ref) 318 session->ref(session); 319 read_unlock_bh(&tunnel->hlist_lock); 320 321 return session; 322 } 323 } 324 read_unlock_bh(&tunnel->hlist_lock); 325 326 return NULL; 327 } 328 EXPORT_SYMBOL_GPL(l2tp_session_get); 329 330 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth, 331 bool do_ref) 332 { 333 int hash; 334 struct l2tp_session *session; 335 int count = 0; 336 337 read_lock_bh(&tunnel->hlist_lock); 338 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { 339 hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) { 340 if (++count > nth) { 341 l2tp_session_inc_refcount(session); 342 if (do_ref && session->ref) 343 session->ref(session); 344 read_unlock_bh(&tunnel->hlist_lock); 345 return session; 346 } 347 } 348 } 349 350 read_unlock_bh(&tunnel->hlist_lock); 351 352 return NULL; 353 } 354 EXPORT_SYMBOL_GPL(l2tp_session_get_nth); 355 356 /* Lookup a session by interface name. 357 * This is very inefficient but is only used by management interfaces. 358 */ 359 struct l2tp_session *l2tp_session_get_by_ifname(struct net *net, char *ifname, 360 bool do_ref) 361 { 362 struct l2tp_net *pn = l2tp_pernet(net); 363 int hash; 364 struct l2tp_session *session; 365 366 rcu_read_lock_bh(); 367 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) { 368 hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) { 369 if (!strcmp(session->ifname, ifname)) { 370 l2tp_session_inc_refcount(session); 371 if (do_ref && session->ref) 372 session->ref(session); 373 rcu_read_unlock_bh(); 374 375 return session; 376 } 377 } 378 } 379 380 rcu_read_unlock_bh(); 381 382 return NULL; 383 } 384 EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname); 385 386 static int l2tp_session_add_to_tunnel(struct l2tp_tunnel *tunnel, 387 struct l2tp_session *session) 388 { 389 struct l2tp_session *session_walk; 390 struct hlist_head *g_head; 391 struct hlist_head *head; 392 struct l2tp_net *pn; 393 394 head = l2tp_session_id_hash(tunnel, session->session_id); 395 396 write_lock_bh(&tunnel->hlist_lock); 397 hlist_for_each_entry(session_walk, head, hlist) 398 if (session_walk->session_id == session->session_id) 399 goto exist; 400 401 if (tunnel->version == L2TP_HDR_VER_3) { 402 pn = l2tp_pernet(tunnel->l2tp_net); 403 g_head = l2tp_session_id_hash_2(l2tp_pernet(tunnel->l2tp_net), 404 session->session_id); 405 406 spin_lock_bh(&pn->l2tp_session_hlist_lock); 407 hlist_for_each_entry(session_walk, g_head, global_hlist) 408 if (session_walk->session_id == session->session_id) 409 goto exist_glob; 410 411 hlist_add_head_rcu(&session->global_hlist, g_head); 412 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 413 } 414 415 hlist_add_head(&session->hlist, head); 416 write_unlock_bh(&tunnel->hlist_lock); 417 418 return 0; 419 420 exist_glob: 421 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 422 exist: 423 write_unlock_bh(&tunnel->hlist_lock); 424 425 return -EEXIST; 426 } 427 428 /* Lookup a tunnel by id 429 */ 430 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id) 431 { 432 struct l2tp_tunnel *tunnel; 433 struct l2tp_net *pn = l2tp_pernet(net); 434 435 rcu_read_lock_bh(); 436 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 437 if (tunnel->tunnel_id == tunnel_id) { 438 rcu_read_unlock_bh(); 439 return tunnel; 440 } 441 } 442 rcu_read_unlock_bh(); 443 444 return NULL; 445 } 446 EXPORT_SYMBOL_GPL(l2tp_tunnel_find); 447 448 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth) 449 { 450 struct l2tp_net *pn = l2tp_pernet(net); 451 struct l2tp_tunnel *tunnel; 452 int count = 0; 453 454 rcu_read_lock_bh(); 455 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 456 if (++count > nth) { 457 rcu_read_unlock_bh(); 458 return tunnel; 459 } 460 } 461 462 rcu_read_unlock_bh(); 463 464 return NULL; 465 } 466 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); 467 468 /***************************************************************************** 469 * Receive data handling 470 *****************************************************************************/ 471 472 /* Queue a skb in order. We come here only if the skb has an L2TP sequence 473 * number. 474 */ 475 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) 476 { 477 struct sk_buff *skbp; 478 struct sk_buff *tmp; 479 u32 ns = L2TP_SKB_CB(skb)->ns; 480 481 spin_lock_bh(&session->reorder_q.lock); 482 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { 483 if (L2TP_SKB_CB(skbp)->ns > ns) { 484 __skb_queue_before(&session->reorder_q, skbp, skb); 485 l2tp_dbg(session, L2TP_MSG_SEQ, 486 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", 487 session->name, ns, L2TP_SKB_CB(skbp)->ns, 488 skb_queue_len(&session->reorder_q)); 489 atomic_long_inc(&session->stats.rx_oos_packets); 490 goto out; 491 } 492 } 493 494 __skb_queue_tail(&session->reorder_q, skb); 495 496 out: 497 spin_unlock_bh(&session->reorder_q.lock); 498 } 499 500 /* Dequeue a single skb. 501 */ 502 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) 503 { 504 struct l2tp_tunnel *tunnel = session->tunnel; 505 int length = L2TP_SKB_CB(skb)->length; 506 507 /* We're about to requeue the skb, so return resources 508 * to its current owner (a socket receive buffer). 509 */ 510 skb_orphan(skb); 511 512 atomic_long_inc(&tunnel->stats.rx_packets); 513 atomic_long_add(length, &tunnel->stats.rx_bytes); 514 atomic_long_inc(&session->stats.rx_packets); 515 atomic_long_add(length, &session->stats.rx_bytes); 516 517 if (L2TP_SKB_CB(skb)->has_seq) { 518 /* Bump our Nr */ 519 session->nr++; 520 session->nr &= session->nr_max; 521 522 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n", 523 session->name, session->nr); 524 } 525 526 /* call private receive handler */ 527 if (session->recv_skb != NULL) 528 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); 529 else 530 kfree_skb(skb); 531 532 if (session->deref) 533 (*session->deref)(session); 534 } 535 536 /* Dequeue skbs from the session's reorder_q, subject to packet order. 537 * Skbs that have been in the queue for too long are simply discarded. 538 */ 539 static void l2tp_recv_dequeue(struct l2tp_session *session) 540 { 541 struct sk_buff *skb; 542 struct sk_buff *tmp; 543 544 /* If the pkt at the head of the queue has the nr that we 545 * expect to send up next, dequeue it and any other 546 * in-sequence packets behind it. 547 */ 548 start: 549 spin_lock_bh(&session->reorder_q.lock); 550 skb_queue_walk_safe(&session->reorder_q, skb, tmp) { 551 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { 552 atomic_long_inc(&session->stats.rx_seq_discards); 553 atomic_long_inc(&session->stats.rx_errors); 554 l2tp_dbg(session, L2TP_MSG_SEQ, 555 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n", 556 session->name, L2TP_SKB_CB(skb)->ns, 557 L2TP_SKB_CB(skb)->length, session->nr, 558 skb_queue_len(&session->reorder_q)); 559 session->reorder_skip = 1; 560 __skb_unlink(skb, &session->reorder_q); 561 kfree_skb(skb); 562 if (session->deref) 563 (*session->deref)(session); 564 continue; 565 } 566 567 if (L2TP_SKB_CB(skb)->has_seq) { 568 if (session->reorder_skip) { 569 l2tp_dbg(session, L2TP_MSG_SEQ, 570 "%s: advancing nr to next pkt: %u -> %u", 571 session->name, session->nr, 572 L2TP_SKB_CB(skb)->ns); 573 session->reorder_skip = 0; 574 session->nr = L2TP_SKB_CB(skb)->ns; 575 } 576 if (L2TP_SKB_CB(skb)->ns != session->nr) { 577 l2tp_dbg(session, L2TP_MSG_SEQ, 578 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n", 579 session->name, L2TP_SKB_CB(skb)->ns, 580 L2TP_SKB_CB(skb)->length, session->nr, 581 skb_queue_len(&session->reorder_q)); 582 goto out; 583 } 584 } 585 __skb_unlink(skb, &session->reorder_q); 586 587 /* Process the skb. We release the queue lock while we 588 * do so to let other contexts process the queue. 589 */ 590 spin_unlock_bh(&session->reorder_q.lock); 591 l2tp_recv_dequeue_skb(session, skb); 592 goto start; 593 } 594 595 out: 596 spin_unlock_bh(&session->reorder_q.lock); 597 } 598 599 static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr) 600 { 601 u32 nws; 602 603 if (nr >= session->nr) 604 nws = nr - session->nr; 605 else 606 nws = (session->nr_max + 1) - (session->nr - nr); 607 608 return nws < session->nr_window_size; 609 } 610 611 /* If packet has sequence numbers, queue it if acceptable. Returns 0 if 612 * acceptable, else non-zero. 613 */ 614 static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb) 615 { 616 if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) { 617 /* Packet sequence number is outside allowed window. 618 * Discard it. 619 */ 620 l2tp_dbg(session, L2TP_MSG_SEQ, 621 "%s: pkt %u len %d discarded, outside window, nr=%u\n", 622 session->name, L2TP_SKB_CB(skb)->ns, 623 L2TP_SKB_CB(skb)->length, session->nr); 624 goto discard; 625 } 626 627 if (session->reorder_timeout != 0) { 628 /* Packet reordering enabled. Add skb to session's 629 * reorder queue, in order of ns. 630 */ 631 l2tp_recv_queue_skb(session, skb); 632 goto out; 633 } 634 635 /* Packet reordering disabled. Discard out-of-sequence packets, while 636 * tracking the number if in-sequence packets after the first OOS packet 637 * is seen. After nr_oos_count_max in-sequence packets, reset the 638 * sequence number to re-enable packet reception. 639 */ 640 if (L2TP_SKB_CB(skb)->ns == session->nr) { 641 skb_queue_tail(&session->reorder_q, skb); 642 } else { 643 u32 nr_oos = L2TP_SKB_CB(skb)->ns; 644 u32 nr_next = (session->nr_oos + 1) & session->nr_max; 645 646 if (nr_oos == nr_next) 647 session->nr_oos_count++; 648 else 649 session->nr_oos_count = 0; 650 651 session->nr_oos = nr_oos; 652 if (session->nr_oos_count > session->nr_oos_count_max) { 653 session->reorder_skip = 1; 654 l2tp_dbg(session, L2TP_MSG_SEQ, 655 "%s: %d oos packets received. Resetting sequence numbers\n", 656 session->name, session->nr_oos_count); 657 } 658 if (!session->reorder_skip) { 659 atomic_long_inc(&session->stats.rx_seq_discards); 660 l2tp_dbg(session, L2TP_MSG_SEQ, 661 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n", 662 session->name, L2TP_SKB_CB(skb)->ns, 663 L2TP_SKB_CB(skb)->length, session->nr, 664 skb_queue_len(&session->reorder_q)); 665 goto discard; 666 } 667 skb_queue_tail(&session->reorder_q, skb); 668 } 669 670 out: 671 return 0; 672 673 discard: 674 return 1; 675 } 676 677 /* Do receive processing of L2TP data frames. We handle both L2TPv2 678 * and L2TPv3 data frames here. 679 * 680 * L2TPv2 Data Message Header 681 * 682 * 0 1 2 3 683 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 684 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 685 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | 686 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 687 * | Tunnel ID | Session ID | 688 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 689 * | Ns (opt) | Nr (opt) | 690 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 691 * | Offset Size (opt) | Offset pad... (opt) 692 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 693 * 694 * Data frames are marked by T=0. All other fields are the same as 695 * those in L2TP control frames. 696 * 697 * L2TPv3 Data Message Header 698 * 699 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 700 * | L2TP Session Header | 701 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 702 * | L2-Specific Sublayer | 703 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 704 * | Tunnel Payload ... 705 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 706 * 707 * L2TPv3 Session Header Over IP 708 * 709 * 0 1 2 3 710 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 711 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 712 * | Session ID | 713 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 714 * | Cookie (optional, maximum 64 bits)... 715 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 716 * | 717 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 718 * 719 * L2TPv3 L2-Specific Sublayer Format 720 * 721 * 0 1 2 3 722 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 723 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 724 * |x|S|x|x|x|x|x|x| Sequence Number | 725 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 726 * 727 * Cookie value, sublayer format and offset (pad) are negotiated with 728 * the peer when the session is set up. Unlike L2TPv2, we do not need 729 * to parse the packet header to determine if optional fields are 730 * present. 731 * 732 * Caller must already have parsed the frame and determined that it is 733 * a data (not control) frame before coming here. Fields up to the 734 * session-id have already been parsed and ptr points to the data 735 * after the session-id. 736 * 737 * session->ref() must have been called prior to l2tp_recv_common(). 738 * session->deref() will be called automatically after skb is processed. 739 */ 740 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 741 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 742 int length, int (*payload_hook)(struct sk_buff *skb)) 743 { 744 struct l2tp_tunnel *tunnel = session->tunnel; 745 int offset; 746 u32 ns, nr; 747 748 /* Parse and check optional cookie */ 749 if (session->peer_cookie_len > 0) { 750 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { 751 l2tp_info(tunnel, L2TP_MSG_DATA, 752 "%s: cookie mismatch (%u/%u). Discarding.\n", 753 tunnel->name, tunnel->tunnel_id, 754 session->session_id); 755 atomic_long_inc(&session->stats.rx_cookie_discards); 756 goto discard; 757 } 758 ptr += session->peer_cookie_len; 759 } 760 761 /* Handle the optional sequence numbers. Sequence numbers are 762 * in different places for L2TPv2 and L2TPv3. 763 * 764 * If we are the LAC, enable/disable sequence numbers under 765 * the control of the LNS. If no sequence numbers present but 766 * we were expecting them, discard frame. 767 */ 768 ns = nr = 0; 769 L2TP_SKB_CB(skb)->has_seq = 0; 770 if (tunnel->version == L2TP_HDR_VER_2) { 771 if (hdrflags & L2TP_HDRFLAG_S) { 772 ns = ntohs(*(__be16 *) ptr); 773 ptr += 2; 774 nr = ntohs(*(__be16 *) ptr); 775 ptr += 2; 776 777 /* Store L2TP info in the skb */ 778 L2TP_SKB_CB(skb)->ns = ns; 779 L2TP_SKB_CB(skb)->has_seq = 1; 780 781 l2tp_dbg(session, L2TP_MSG_SEQ, 782 "%s: recv data ns=%u, nr=%u, session nr=%u\n", 783 session->name, ns, nr, session->nr); 784 } 785 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 786 u32 l2h = ntohl(*(__be32 *) ptr); 787 788 if (l2h & 0x40000000) { 789 ns = l2h & 0x00ffffff; 790 791 /* Store L2TP info in the skb */ 792 L2TP_SKB_CB(skb)->ns = ns; 793 L2TP_SKB_CB(skb)->has_seq = 1; 794 795 l2tp_dbg(session, L2TP_MSG_SEQ, 796 "%s: recv data ns=%u, session nr=%u\n", 797 session->name, ns, session->nr); 798 } 799 } 800 801 /* Advance past L2-specific header, if present */ 802 ptr += session->l2specific_len; 803 804 if (L2TP_SKB_CB(skb)->has_seq) { 805 /* Received a packet with sequence numbers. If we're the LNS, 806 * check if we sre sending sequence numbers and if not, 807 * configure it so. 808 */ 809 if ((!session->lns_mode) && (!session->send_seq)) { 810 l2tp_info(session, L2TP_MSG_SEQ, 811 "%s: requested to enable seq numbers by LNS\n", 812 session->name); 813 session->send_seq = 1; 814 l2tp_session_set_header_len(session, tunnel->version); 815 } 816 } else { 817 /* No sequence numbers. 818 * If user has configured mandatory sequence numbers, discard. 819 */ 820 if (session->recv_seq) { 821 l2tp_warn(session, L2TP_MSG_SEQ, 822 "%s: recv data has no seq numbers when required. Discarding.\n", 823 session->name); 824 atomic_long_inc(&session->stats.rx_seq_discards); 825 goto discard; 826 } 827 828 /* If we're the LAC and we're sending sequence numbers, the 829 * LNS has requested that we no longer send sequence numbers. 830 * If we're the LNS and we're sending sequence numbers, the 831 * LAC is broken. Discard the frame. 832 */ 833 if ((!session->lns_mode) && (session->send_seq)) { 834 l2tp_info(session, L2TP_MSG_SEQ, 835 "%s: requested to disable seq numbers by LNS\n", 836 session->name); 837 session->send_seq = 0; 838 l2tp_session_set_header_len(session, tunnel->version); 839 } else if (session->send_seq) { 840 l2tp_warn(session, L2TP_MSG_SEQ, 841 "%s: recv data has no seq numbers when required. Discarding.\n", 842 session->name); 843 atomic_long_inc(&session->stats.rx_seq_discards); 844 goto discard; 845 } 846 } 847 848 /* Session data offset is handled differently for L2TPv2 and 849 * L2TPv3. For L2TPv2, there is an optional 16-bit value in 850 * the header. For L2TPv3, the offset is negotiated using AVPs 851 * in the session setup control protocol. 852 */ 853 if (tunnel->version == L2TP_HDR_VER_2) { 854 /* If offset bit set, skip it. */ 855 if (hdrflags & L2TP_HDRFLAG_O) { 856 offset = ntohs(*(__be16 *)ptr); 857 ptr += 2 + offset; 858 } 859 } else 860 ptr += session->offset; 861 862 offset = ptr - optr; 863 if (!pskb_may_pull(skb, offset)) 864 goto discard; 865 866 __skb_pull(skb, offset); 867 868 /* If caller wants to process the payload before we queue the 869 * packet, do so now. 870 */ 871 if (payload_hook) 872 if ((*payload_hook)(skb)) 873 goto discard; 874 875 /* Prepare skb for adding to the session's reorder_q. Hold 876 * packets for max reorder_timeout or 1 second if not 877 * reordering. 878 */ 879 L2TP_SKB_CB(skb)->length = length; 880 L2TP_SKB_CB(skb)->expires = jiffies + 881 (session->reorder_timeout ? session->reorder_timeout : HZ); 882 883 /* Add packet to the session's receive queue. Reordering is done here, if 884 * enabled. Saved L2TP protocol info is stored in skb->sb[]. 885 */ 886 if (L2TP_SKB_CB(skb)->has_seq) { 887 if (l2tp_recv_data_seq(session, skb)) 888 goto discard; 889 } else { 890 /* No sequence numbers. Add the skb to the tail of the 891 * reorder queue. This ensures that it will be 892 * delivered after all previous sequenced skbs. 893 */ 894 skb_queue_tail(&session->reorder_q, skb); 895 } 896 897 /* Try to dequeue as many skbs from reorder_q as we can. */ 898 l2tp_recv_dequeue(session); 899 900 return; 901 902 discard: 903 atomic_long_inc(&session->stats.rx_errors); 904 kfree_skb(skb); 905 906 if (session->deref) 907 (*session->deref)(session); 908 } 909 EXPORT_SYMBOL(l2tp_recv_common); 910 911 /* Drop skbs from the session's reorder_q 912 */ 913 int l2tp_session_queue_purge(struct l2tp_session *session) 914 { 915 struct sk_buff *skb = NULL; 916 BUG_ON(!session); 917 BUG_ON(session->magic != L2TP_SESSION_MAGIC); 918 while ((skb = skb_dequeue(&session->reorder_q))) { 919 atomic_long_inc(&session->stats.rx_errors); 920 kfree_skb(skb); 921 if (session->deref) 922 (*session->deref)(session); 923 } 924 return 0; 925 } 926 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge); 927 928 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame 929 * here. The skb is not on a list when we get here. 930 * Returns 0 if the packet was a data packet and was successfully passed on. 931 * Returns 1 if the packet was not a good data packet and could not be 932 * forwarded. All such packets are passed up to userspace to deal with. 933 */ 934 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, 935 int (*payload_hook)(struct sk_buff *skb)) 936 { 937 struct l2tp_session *session = NULL; 938 unsigned char *ptr, *optr; 939 u16 hdrflags; 940 u32 tunnel_id, session_id; 941 u16 version; 942 int length; 943 944 /* UDP has verifed checksum */ 945 946 /* UDP always verifies the packet length. */ 947 __skb_pull(skb, sizeof(struct udphdr)); 948 949 /* Short packet? */ 950 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { 951 l2tp_info(tunnel, L2TP_MSG_DATA, 952 "%s: recv short packet (len=%d)\n", 953 tunnel->name, skb->len); 954 goto error; 955 } 956 957 /* Trace packet contents, if enabled */ 958 if (tunnel->debug & L2TP_MSG_DATA) { 959 length = min(32u, skb->len); 960 if (!pskb_may_pull(skb, length)) 961 goto error; 962 963 pr_debug("%s: recv\n", tunnel->name); 964 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length); 965 } 966 967 /* Point to L2TP header */ 968 optr = ptr = skb->data; 969 970 /* Get L2TP header flags */ 971 hdrflags = ntohs(*(__be16 *) ptr); 972 973 /* Check protocol version */ 974 version = hdrflags & L2TP_HDR_VER_MASK; 975 if (version != tunnel->version) { 976 l2tp_info(tunnel, L2TP_MSG_DATA, 977 "%s: recv protocol version mismatch: got %d expected %d\n", 978 tunnel->name, version, tunnel->version); 979 goto error; 980 } 981 982 /* Get length of L2TP packet */ 983 length = skb->len; 984 985 /* If type is control packet, it is handled by userspace. */ 986 if (hdrflags & L2TP_HDRFLAG_T) { 987 l2tp_dbg(tunnel, L2TP_MSG_DATA, 988 "%s: recv control packet, len=%d\n", 989 tunnel->name, length); 990 goto error; 991 } 992 993 /* Skip flags */ 994 ptr += 2; 995 996 if (tunnel->version == L2TP_HDR_VER_2) { 997 /* If length is present, skip it */ 998 if (hdrflags & L2TP_HDRFLAG_L) 999 ptr += 2; 1000 1001 /* Extract tunnel and session ID */ 1002 tunnel_id = ntohs(*(__be16 *) ptr); 1003 ptr += 2; 1004 session_id = ntohs(*(__be16 *) ptr); 1005 ptr += 2; 1006 } else { 1007 ptr += 2; /* skip reserved bits */ 1008 tunnel_id = tunnel->tunnel_id; 1009 session_id = ntohl(*(__be32 *) ptr); 1010 ptr += 4; 1011 } 1012 1013 /* Find the session context */ 1014 session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id, true); 1015 if (!session || !session->recv_skb) { 1016 if (session) { 1017 if (session->deref) 1018 session->deref(session); 1019 l2tp_session_dec_refcount(session); 1020 } 1021 1022 /* Not found? Pass to userspace to deal with */ 1023 l2tp_info(tunnel, L2TP_MSG_DATA, 1024 "%s: no session found (%u/%u). Passing up.\n", 1025 tunnel->name, tunnel_id, session_id); 1026 goto error; 1027 } 1028 1029 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); 1030 l2tp_session_dec_refcount(session); 1031 1032 return 0; 1033 1034 error: 1035 /* Put UDP header back */ 1036 __skb_push(skb, sizeof(struct udphdr)); 1037 1038 return 1; 1039 } 1040 1041 /* UDP encapsulation receive handler. See net/ipv4/udp.c. 1042 * Return codes: 1043 * 0 : success. 1044 * <0: error 1045 * >0: skb should be passed up to userspace as UDP. 1046 */ 1047 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 1048 { 1049 struct l2tp_tunnel *tunnel; 1050 1051 tunnel = l2tp_sock_to_tunnel(sk); 1052 if (tunnel == NULL) 1053 goto pass_up; 1054 1055 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n", 1056 tunnel->name, skb->len); 1057 1058 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) 1059 goto pass_up_put; 1060 1061 sock_put(sk); 1062 return 0; 1063 1064 pass_up_put: 1065 sock_put(sk); 1066 pass_up: 1067 return 1; 1068 } 1069 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); 1070 1071 /************************************************************************ 1072 * Transmit handling 1073 ***********************************************************************/ 1074 1075 /* Build an L2TP header for the session into the buffer provided. 1076 */ 1077 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) 1078 { 1079 struct l2tp_tunnel *tunnel = session->tunnel; 1080 __be16 *bufp = buf; 1081 __be16 *optr = buf; 1082 u16 flags = L2TP_HDR_VER_2; 1083 u32 tunnel_id = tunnel->peer_tunnel_id; 1084 u32 session_id = session->peer_session_id; 1085 1086 if (session->send_seq) 1087 flags |= L2TP_HDRFLAG_S; 1088 1089 /* Setup L2TP header. */ 1090 *bufp++ = htons(flags); 1091 *bufp++ = htons(tunnel_id); 1092 *bufp++ = htons(session_id); 1093 if (session->send_seq) { 1094 *bufp++ = htons(session->ns); 1095 *bufp++ = 0; 1096 session->ns++; 1097 session->ns &= 0xffff; 1098 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n", 1099 session->name, session->ns); 1100 } 1101 1102 return bufp - optr; 1103 } 1104 1105 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) 1106 { 1107 struct l2tp_tunnel *tunnel = session->tunnel; 1108 char *bufp = buf; 1109 char *optr = bufp; 1110 1111 /* Setup L2TP header. The header differs slightly for UDP and 1112 * IP encapsulations. For UDP, there is 4 bytes of flags. 1113 */ 1114 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { 1115 u16 flags = L2TP_HDR_VER_3; 1116 *((__be16 *) bufp) = htons(flags); 1117 bufp += 2; 1118 *((__be16 *) bufp) = 0; 1119 bufp += 2; 1120 } 1121 1122 *((__be32 *) bufp) = htonl(session->peer_session_id); 1123 bufp += 4; 1124 if (session->cookie_len) { 1125 memcpy(bufp, &session->cookie[0], session->cookie_len); 1126 bufp += session->cookie_len; 1127 } 1128 if (session->l2specific_len) { 1129 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 1130 u32 l2h = 0; 1131 if (session->send_seq) { 1132 l2h = 0x40000000 | session->ns; 1133 session->ns++; 1134 session->ns &= 0xffffff; 1135 l2tp_dbg(session, L2TP_MSG_SEQ, 1136 "%s: updated ns to %u\n", 1137 session->name, session->ns); 1138 } 1139 1140 *((__be32 *) bufp) = htonl(l2h); 1141 } 1142 bufp += session->l2specific_len; 1143 } 1144 if (session->offset) 1145 bufp += session->offset; 1146 1147 return bufp - optr; 1148 } 1149 1150 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, 1151 struct flowi *fl, size_t data_len) 1152 { 1153 struct l2tp_tunnel *tunnel = session->tunnel; 1154 unsigned int len = skb->len; 1155 int error; 1156 1157 /* Debug */ 1158 if (session->send_seq) 1159 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes, ns=%u\n", 1160 session->name, data_len, session->ns - 1); 1161 else 1162 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes\n", 1163 session->name, data_len); 1164 1165 if (session->debug & L2TP_MSG_DATA) { 1166 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; 1167 unsigned char *datap = skb->data + uhlen; 1168 1169 pr_debug("%s: xmit\n", session->name); 1170 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, 1171 datap, min_t(size_t, 32, len - uhlen)); 1172 } 1173 1174 /* Queue the packet to IP for output */ 1175 skb->ignore_df = 1; 1176 #if IS_ENABLED(CONFIG_IPV6) 1177 if (tunnel->sock->sk_family == PF_INET6 && !tunnel->v4mapped) 1178 error = inet6_csk_xmit(tunnel->sock, skb, NULL); 1179 else 1180 #endif 1181 error = ip_queue_xmit(tunnel->sock, skb, fl); 1182 1183 /* Update stats */ 1184 if (error >= 0) { 1185 atomic_long_inc(&tunnel->stats.tx_packets); 1186 atomic_long_add(len, &tunnel->stats.tx_bytes); 1187 atomic_long_inc(&session->stats.tx_packets); 1188 atomic_long_add(len, &session->stats.tx_bytes); 1189 } else { 1190 atomic_long_inc(&tunnel->stats.tx_errors); 1191 atomic_long_inc(&session->stats.tx_errors); 1192 } 1193 1194 return 0; 1195 } 1196 1197 /* If caller requires the skb to have a ppp header, the header must be 1198 * inserted in the skb data before calling this function. 1199 */ 1200 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) 1201 { 1202 int data_len = skb->len; 1203 struct l2tp_tunnel *tunnel = session->tunnel; 1204 struct sock *sk = tunnel->sock; 1205 struct flowi *fl; 1206 struct udphdr *uh; 1207 struct inet_sock *inet; 1208 int headroom; 1209 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; 1210 int udp_len; 1211 int ret = NET_XMIT_SUCCESS; 1212 1213 /* Check that there's enough headroom in the skb to insert IP, 1214 * UDP and L2TP headers. If not enough, expand it to 1215 * make room. Adjust truesize. 1216 */ 1217 headroom = NET_SKB_PAD + sizeof(struct iphdr) + 1218 uhlen + hdr_len; 1219 if (skb_cow_head(skb, headroom)) { 1220 kfree_skb(skb); 1221 return NET_XMIT_DROP; 1222 } 1223 1224 /* Setup L2TP header */ 1225 session->build_header(session, __skb_push(skb, hdr_len)); 1226 1227 /* Reset skb netfilter state */ 1228 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 1229 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | 1230 IPSKB_REROUTED); 1231 nf_reset(skb); 1232 1233 bh_lock_sock(sk); 1234 if (sock_owned_by_user(sk)) { 1235 kfree_skb(skb); 1236 ret = NET_XMIT_DROP; 1237 goto out_unlock; 1238 } 1239 1240 /* Get routing info from the tunnel socket */ 1241 skb_dst_drop(skb); 1242 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0))); 1243 1244 inet = inet_sk(sk); 1245 fl = &inet->cork.fl; 1246 switch (tunnel->encap) { 1247 case L2TP_ENCAPTYPE_UDP: 1248 /* Setup UDP header */ 1249 __skb_push(skb, sizeof(*uh)); 1250 skb_reset_transport_header(skb); 1251 uh = udp_hdr(skb); 1252 uh->source = inet->inet_sport; 1253 uh->dest = inet->inet_dport; 1254 udp_len = uhlen + hdr_len + data_len; 1255 uh->len = htons(udp_len); 1256 1257 /* Calculate UDP checksum if configured to do so */ 1258 #if IS_ENABLED(CONFIG_IPV6) 1259 if (sk->sk_family == PF_INET6 && !tunnel->v4mapped) 1260 udp6_set_csum(udp_get_no_check6_tx(sk), 1261 skb, &inet6_sk(sk)->saddr, 1262 &sk->sk_v6_daddr, udp_len); 1263 else 1264 #endif 1265 udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr, 1266 inet->inet_daddr, udp_len); 1267 break; 1268 1269 case L2TP_ENCAPTYPE_IP: 1270 break; 1271 } 1272 1273 l2tp_xmit_core(session, skb, fl, data_len); 1274 out_unlock: 1275 bh_unlock_sock(sk); 1276 1277 return ret; 1278 } 1279 EXPORT_SYMBOL_GPL(l2tp_xmit_skb); 1280 1281 /***************************************************************************** 1282 * Tinnel and session create/destroy. 1283 *****************************************************************************/ 1284 1285 /* Tunnel socket destruct hook. 1286 * The tunnel context is deleted only when all session sockets have been 1287 * closed. 1288 */ 1289 static void l2tp_tunnel_destruct(struct sock *sk) 1290 { 1291 struct l2tp_tunnel *tunnel = l2tp_tunnel(sk); 1292 struct l2tp_net *pn; 1293 1294 if (tunnel == NULL) 1295 goto end; 1296 1297 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name); 1298 1299 1300 /* Disable udp encapsulation */ 1301 switch (tunnel->encap) { 1302 case L2TP_ENCAPTYPE_UDP: 1303 /* No longer an encapsulation socket. See net/ipv4/udp.c */ 1304 (udp_sk(sk))->encap_type = 0; 1305 (udp_sk(sk))->encap_rcv = NULL; 1306 (udp_sk(sk))->encap_destroy = NULL; 1307 break; 1308 case L2TP_ENCAPTYPE_IP: 1309 break; 1310 } 1311 1312 /* Remove hooks into tunnel socket */ 1313 sk->sk_destruct = tunnel->old_sk_destruct; 1314 sk->sk_user_data = NULL; 1315 tunnel->sock = NULL; 1316 1317 /* Remove the tunnel struct from the tunnel list */ 1318 pn = l2tp_pernet(tunnel->l2tp_net); 1319 spin_lock_bh(&pn->l2tp_tunnel_list_lock); 1320 list_del_rcu(&tunnel->list); 1321 spin_unlock_bh(&pn->l2tp_tunnel_list_lock); 1322 atomic_dec(&l2tp_tunnel_count); 1323 1324 l2tp_tunnel_closeall(tunnel); 1325 l2tp_tunnel_dec_refcount(tunnel); 1326 1327 /* Call the original destructor */ 1328 if (sk->sk_destruct) 1329 (*sk->sk_destruct)(sk); 1330 end: 1331 return; 1332 } 1333 1334 /* When the tunnel is closed, all the attached sessions need to go too. 1335 */ 1336 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) 1337 { 1338 int hash; 1339 struct hlist_node *walk; 1340 struct hlist_node *tmp; 1341 struct l2tp_session *session; 1342 1343 BUG_ON(tunnel == NULL); 1344 1345 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n", 1346 tunnel->name); 1347 1348 write_lock_bh(&tunnel->hlist_lock); 1349 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { 1350 again: 1351 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { 1352 session = hlist_entry(walk, struct l2tp_session, hlist); 1353 1354 l2tp_info(session, L2TP_MSG_CONTROL, 1355 "%s: closing session\n", session->name); 1356 1357 hlist_del_init(&session->hlist); 1358 1359 if (session->ref != NULL) 1360 (*session->ref)(session); 1361 1362 write_unlock_bh(&tunnel->hlist_lock); 1363 1364 __l2tp_session_unhash(session); 1365 l2tp_session_queue_purge(session); 1366 1367 if (session->session_close != NULL) 1368 (*session->session_close)(session); 1369 1370 if (session->deref != NULL) 1371 (*session->deref)(session); 1372 1373 l2tp_session_dec_refcount(session); 1374 1375 write_lock_bh(&tunnel->hlist_lock); 1376 1377 /* Now restart from the beginning of this hash 1378 * chain. We always remove a session from the 1379 * list so we are guaranteed to make forward 1380 * progress. 1381 */ 1382 goto again; 1383 } 1384 } 1385 write_unlock_bh(&tunnel->hlist_lock); 1386 } 1387 EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall); 1388 1389 /* Tunnel socket destroy hook for UDP encapsulation */ 1390 static void l2tp_udp_encap_destroy(struct sock *sk) 1391 { 1392 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); 1393 if (tunnel) { 1394 l2tp_tunnel_closeall(tunnel); 1395 sock_put(sk); 1396 } 1397 } 1398 1399 /* Really kill the tunnel. 1400 * Come here only when all sessions have been cleared from the tunnel. 1401 */ 1402 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) 1403 { 1404 BUG_ON(atomic_read(&tunnel->ref_count) != 0); 1405 BUG_ON(tunnel->sock != NULL); 1406 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name); 1407 kfree_rcu(tunnel, rcu); 1408 } 1409 1410 /* Workqueue tunnel deletion function */ 1411 static void l2tp_tunnel_del_work(struct work_struct *work) 1412 { 1413 struct l2tp_tunnel *tunnel = NULL; 1414 struct socket *sock = NULL; 1415 struct sock *sk = NULL; 1416 1417 tunnel = container_of(work, struct l2tp_tunnel, del_work); 1418 1419 l2tp_tunnel_closeall(tunnel); 1420 1421 sk = l2tp_tunnel_sock_lookup(tunnel); 1422 if (!sk) 1423 goto out; 1424 1425 sock = sk->sk_socket; 1426 1427 /* If the tunnel socket was created by userspace, then go through the 1428 * inet layer to shut the socket down, and let userspace close it. 1429 * Otherwise, if we created the socket directly within the kernel, use 1430 * the sk API to release it here. 1431 * In either case the tunnel resources are freed in the socket 1432 * destructor when the tunnel socket goes away. 1433 */ 1434 if (tunnel->fd >= 0) { 1435 if (sock) 1436 inet_shutdown(sock, 2); 1437 } else { 1438 if (sock) { 1439 kernel_sock_shutdown(sock, SHUT_RDWR); 1440 sock_release(sock); 1441 } 1442 } 1443 1444 l2tp_tunnel_sock_put(sk); 1445 out: 1446 l2tp_tunnel_dec_refcount(tunnel); 1447 } 1448 1449 /* Create a socket for the tunnel, if one isn't set up by 1450 * userspace. This is used for static tunnels where there is no 1451 * managing L2TP daemon. 1452 * 1453 * Since we don't want these sockets to keep a namespace alive by 1454 * themselves, we drop the socket's namespace refcount after creation. 1455 * These sockets are freed when the namespace exits using the pernet 1456 * exit hook. 1457 */ 1458 static int l2tp_tunnel_sock_create(struct net *net, 1459 u32 tunnel_id, 1460 u32 peer_tunnel_id, 1461 struct l2tp_tunnel_cfg *cfg, 1462 struct socket **sockp) 1463 { 1464 int err = -EINVAL; 1465 struct socket *sock = NULL; 1466 struct udp_port_cfg udp_conf; 1467 1468 switch (cfg->encap) { 1469 case L2TP_ENCAPTYPE_UDP: 1470 memset(&udp_conf, 0, sizeof(udp_conf)); 1471 1472 #if IS_ENABLED(CONFIG_IPV6) 1473 if (cfg->local_ip6 && cfg->peer_ip6) { 1474 udp_conf.family = AF_INET6; 1475 memcpy(&udp_conf.local_ip6, cfg->local_ip6, 1476 sizeof(udp_conf.local_ip6)); 1477 memcpy(&udp_conf.peer_ip6, cfg->peer_ip6, 1478 sizeof(udp_conf.peer_ip6)); 1479 udp_conf.use_udp6_tx_checksums = 1480 ! cfg->udp6_zero_tx_checksums; 1481 udp_conf.use_udp6_rx_checksums = 1482 ! cfg->udp6_zero_rx_checksums; 1483 } else 1484 #endif 1485 { 1486 udp_conf.family = AF_INET; 1487 udp_conf.local_ip = cfg->local_ip; 1488 udp_conf.peer_ip = cfg->peer_ip; 1489 udp_conf.use_udp_checksums = cfg->use_udp_checksums; 1490 } 1491 1492 udp_conf.local_udp_port = htons(cfg->local_udp_port); 1493 udp_conf.peer_udp_port = htons(cfg->peer_udp_port); 1494 1495 err = udp_sock_create(net, &udp_conf, &sock); 1496 if (err < 0) 1497 goto out; 1498 1499 break; 1500 1501 case L2TP_ENCAPTYPE_IP: 1502 #if IS_ENABLED(CONFIG_IPV6) 1503 if (cfg->local_ip6 && cfg->peer_ip6) { 1504 struct sockaddr_l2tpip6 ip6_addr = {0}; 1505 1506 err = sock_create_kern(net, AF_INET6, SOCK_DGRAM, 1507 IPPROTO_L2TP, &sock); 1508 if (err < 0) 1509 goto out; 1510 1511 ip6_addr.l2tp_family = AF_INET6; 1512 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6, 1513 sizeof(ip6_addr.l2tp_addr)); 1514 ip6_addr.l2tp_conn_id = tunnel_id; 1515 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr, 1516 sizeof(ip6_addr)); 1517 if (err < 0) 1518 goto out; 1519 1520 ip6_addr.l2tp_family = AF_INET6; 1521 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6, 1522 sizeof(ip6_addr.l2tp_addr)); 1523 ip6_addr.l2tp_conn_id = peer_tunnel_id; 1524 err = kernel_connect(sock, 1525 (struct sockaddr *) &ip6_addr, 1526 sizeof(ip6_addr), 0); 1527 if (err < 0) 1528 goto out; 1529 } else 1530 #endif 1531 { 1532 struct sockaddr_l2tpip ip_addr = {0}; 1533 1534 err = sock_create_kern(net, AF_INET, SOCK_DGRAM, 1535 IPPROTO_L2TP, &sock); 1536 if (err < 0) 1537 goto out; 1538 1539 ip_addr.l2tp_family = AF_INET; 1540 ip_addr.l2tp_addr = cfg->local_ip; 1541 ip_addr.l2tp_conn_id = tunnel_id; 1542 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, 1543 sizeof(ip_addr)); 1544 if (err < 0) 1545 goto out; 1546 1547 ip_addr.l2tp_family = AF_INET; 1548 ip_addr.l2tp_addr = cfg->peer_ip; 1549 ip_addr.l2tp_conn_id = peer_tunnel_id; 1550 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, 1551 sizeof(ip_addr), 0); 1552 if (err < 0) 1553 goto out; 1554 } 1555 break; 1556 1557 default: 1558 goto out; 1559 } 1560 1561 out: 1562 *sockp = sock; 1563 if ((err < 0) && sock) { 1564 kernel_sock_shutdown(sock, SHUT_RDWR); 1565 sock_release(sock); 1566 *sockp = NULL; 1567 } 1568 1569 return err; 1570 } 1571 1572 static struct lock_class_key l2tp_socket_class; 1573 1574 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp) 1575 { 1576 struct l2tp_tunnel *tunnel = NULL; 1577 int err; 1578 struct socket *sock = NULL; 1579 struct sock *sk = NULL; 1580 struct l2tp_net *pn; 1581 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; 1582 1583 /* Get the tunnel socket from the fd, which was opened by 1584 * the userspace L2TP daemon. If not specified, create a 1585 * kernel socket. 1586 */ 1587 if (fd < 0) { 1588 err = l2tp_tunnel_sock_create(net, tunnel_id, peer_tunnel_id, 1589 cfg, &sock); 1590 if (err < 0) 1591 goto err; 1592 } else { 1593 sock = sockfd_lookup(fd, &err); 1594 if (!sock) { 1595 pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n", 1596 tunnel_id, fd, err); 1597 err = -EBADF; 1598 goto err; 1599 } 1600 1601 /* Reject namespace mismatches */ 1602 if (!net_eq(sock_net(sock->sk), net)) { 1603 pr_err("tunl %u: netns mismatch\n", tunnel_id); 1604 err = -EINVAL; 1605 goto err; 1606 } 1607 } 1608 1609 sk = sock->sk; 1610 1611 if (cfg != NULL) 1612 encap = cfg->encap; 1613 1614 /* Quick sanity checks */ 1615 switch (encap) { 1616 case L2TP_ENCAPTYPE_UDP: 1617 err = -EPROTONOSUPPORT; 1618 if (sk->sk_protocol != IPPROTO_UDP) { 1619 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n", 1620 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); 1621 goto err; 1622 } 1623 break; 1624 case L2TP_ENCAPTYPE_IP: 1625 err = -EPROTONOSUPPORT; 1626 if (sk->sk_protocol != IPPROTO_L2TP) { 1627 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n", 1628 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP); 1629 goto err; 1630 } 1631 break; 1632 } 1633 1634 /* Check if this socket has already been prepped */ 1635 tunnel = l2tp_tunnel(sk); 1636 if (tunnel != NULL) { 1637 /* This socket has already been prepped */ 1638 err = -EBUSY; 1639 goto err; 1640 } 1641 1642 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); 1643 if (tunnel == NULL) { 1644 err = -ENOMEM; 1645 goto err; 1646 } 1647 1648 tunnel->version = version; 1649 tunnel->tunnel_id = tunnel_id; 1650 tunnel->peer_tunnel_id = peer_tunnel_id; 1651 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; 1652 1653 tunnel->magic = L2TP_TUNNEL_MAGIC; 1654 sprintf(&tunnel->name[0], "tunl %u", tunnel_id); 1655 rwlock_init(&tunnel->hlist_lock); 1656 1657 /* The net we belong to */ 1658 tunnel->l2tp_net = net; 1659 pn = l2tp_pernet(net); 1660 1661 if (cfg != NULL) 1662 tunnel->debug = cfg->debug; 1663 1664 #if IS_ENABLED(CONFIG_IPV6) 1665 if (sk->sk_family == PF_INET6) { 1666 struct ipv6_pinfo *np = inet6_sk(sk); 1667 1668 if (ipv6_addr_v4mapped(&np->saddr) && 1669 ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { 1670 struct inet_sock *inet = inet_sk(sk); 1671 1672 tunnel->v4mapped = true; 1673 inet->inet_saddr = np->saddr.s6_addr32[3]; 1674 inet->inet_rcv_saddr = sk->sk_v6_rcv_saddr.s6_addr32[3]; 1675 inet->inet_daddr = sk->sk_v6_daddr.s6_addr32[3]; 1676 } else { 1677 tunnel->v4mapped = false; 1678 } 1679 } 1680 #endif 1681 1682 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ 1683 tunnel->encap = encap; 1684 if (encap == L2TP_ENCAPTYPE_UDP) { 1685 struct udp_tunnel_sock_cfg udp_cfg = { }; 1686 1687 udp_cfg.sk_user_data = tunnel; 1688 udp_cfg.encap_type = UDP_ENCAP_L2TPINUDP; 1689 udp_cfg.encap_rcv = l2tp_udp_encap_recv; 1690 udp_cfg.encap_destroy = l2tp_udp_encap_destroy; 1691 1692 setup_udp_tunnel_sock(net, sock, &udp_cfg); 1693 } else { 1694 sk->sk_user_data = tunnel; 1695 } 1696 1697 /* Hook on the tunnel socket destructor so that we can cleanup 1698 * if the tunnel socket goes away. 1699 */ 1700 tunnel->old_sk_destruct = sk->sk_destruct; 1701 sk->sk_destruct = &l2tp_tunnel_destruct; 1702 tunnel->sock = sk; 1703 tunnel->fd = fd; 1704 lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock"); 1705 1706 sk->sk_allocation = GFP_ATOMIC; 1707 1708 /* Init delete workqueue struct */ 1709 INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work); 1710 1711 /* Add tunnel to our list */ 1712 INIT_LIST_HEAD(&tunnel->list); 1713 atomic_inc(&l2tp_tunnel_count); 1714 1715 /* Bump the reference count. The tunnel context is deleted 1716 * only when this drops to zero. Must be done before list insertion 1717 */ 1718 l2tp_tunnel_inc_refcount(tunnel); 1719 spin_lock_bh(&pn->l2tp_tunnel_list_lock); 1720 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); 1721 spin_unlock_bh(&pn->l2tp_tunnel_list_lock); 1722 1723 err = 0; 1724 err: 1725 if (tunnelp) 1726 *tunnelp = tunnel; 1727 1728 /* If tunnel's socket was created by the kernel, it doesn't 1729 * have a file. 1730 */ 1731 if (sock && sock->file) 1732 sockfd_put(sock); 1733 1734 return err; 1735 } 1736 EXPORT_SYMBOL_GPL(l2tp_tunnel_create); 1737 1738 /* This function is used by the netlink TUNNEL_DELETE command. 1739 */ 1740 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) 1741 { 1742 l2tp_tunnel_inc_refcount(tunnel); 1743 if (false == queue_work(l2tp_wq, &tunnel->del_work)) { 1744 l2tp_tunnel_dec_refcount(tunnel); 1745 return 1; 1746 } 1747 return 0; 1748 } 1749 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); 1750 1751 /* Really kill the session. 1752 */ 1753 void l2tp_session_free(struct l2tp_session *session) 1754 { 1755 struct l2tp_tunnel *tunnel = session->tunnel; 1756 1757 BUG_ON(atomic_read(&session->ref_count) != 0); 1758 1759 if (tunnel) { 1760 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 1761 if (session->session_id != 0) 1762 atomic_dec(&l2tp_session_count); 1763 sock_put(tunnel->sock); 1764 session->tunnel = NULL; 1765 l2tp_tunnel_dec_refcount(tunnel); 1766 } 1767 1768 kfree(session); 1769 } 1770 EXPORT_SYMBOL_GPL(l2tp_session_free); 1771 1772 /* Remove an l2tp session from l2tp_core's hash lists. 1773 * Provides a tidyup interface for pseudowire code which can't just route all 1774 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close 1775 * callback. 1776 */ 1777 void __l2tp_session_unhash(struct l2tp_session *session) 1778 { 1779 struct l2tp_tunnel *tunnel = session->tunnel; 1780 1781 /* Remove the session from core hashes */ 1782 if (tunnel) { 1783 /* Remove from the per-tunnel hash */ 1784 write_lock_bh(&tunnel->hlist_lock); 1785 hlist_del_init(&session->hlist); 1786 write_unlock_bh(&tunnel->hlist_lock); 1787 1788 /* For L2TPv3 we have a per-net hash: remove from there, too */ 1789 if (tunnel->version != L2TP_HDR_VER_2) { 1790 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1791 spin_lock_bh(&pn->l2tp_session_hlist_lock); 1792 hlist_del_init_rcu(&session->global_hlist); 1793 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 1794 synchronize_rcu(); 1795 } 1796 } 1797 } 1798 EXPORT_SYMBOL_GPL(__l2tp_session_unhash); 1799 1800 /* This function is used by the netlink SESSION_DELETE command and by 1801 pseudowire modules. 1802 */ 1803 int l2tp_session_delete(struct l2tp_session *session) 1804 { 1805 if (session->ref) 1806 (*session->ref)(session); 1807 __l2tp_session_unhash(session); 1808 l2tp_session_queue_purge(session); 1809 if (session->session_close != NULL) 1810 (*session->session_close)(session); 1811 if (session->deref) 1812 (*session->deref)(session); 1813 l2tp_session_dec_refcount(session); 1814 return 0; 1815 } 1816 EXPORT_SYMBOL_GPL(l2tp_session_delete); 1817 1818 /* We come here whenever a session's send_seq, cookie_len or 1819 * l2specific_len parameters are set. 1820 */ 1821 void l2tp_session_set_header_len(struct l2tp_session *session, int version) 1822 { 1823 if (version == L2TP_HDR_VER_2) { 1824 session->hdr_len = 6; 1825 if (session->send_seq) 1826 session->hdr_len += 4; 1827 } else { 1828 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset; 1829 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP) 1830 session->hdr_len += 4; 1831 } 1832 1833 } 1834 EXPORT_SYMBOL_GPL(l2tp_session_set_header_len); 1835 1836 struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) 1837 { 1838 struct l2tp_session *session; 1839 int err; 1840 1841 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); 1842 if (session != NULL) { 1843 session->magic = L2TP_SESSION_MAGIC; 1844 session->tunnel = tunnel; 1845 1846 session->session_id = session_id; 1847 session->peer_session_id = peer_session_id; 1848 session->nr = 0; 1849 if (tunnel->version == L2TP_HDR_VER_2) 1850 session->nr_max = 0xffff; 1851 else 1852 session->nr_max = 0xffffff; 1853 session->nr_window_size = session->nr_max / 2; 1854 session->nr_oos_count_max = 4; 1855 1856 /* Use NR of first received packet */ 1857 session->reorder_skip = 1; 1858 1859 sprintf(&session->name[0], "sess %u/%u", 1860 tunnel->tunnel_id, session->session_id); 1861 1862 skb_queue_head_init(&session->reorder_q); 1863 1864 INIT_HLIST_NODE(&session->hlist); 1865 INIT_HLIST_NODE(&session->global_hlist); 1866 1867 /* Inherit debug options from tunnel */ 1868 session->debug = tunnel->debug; 1869 1870 if (cfg) { 1871 session->pwtype = cfg->pw_type; 1872 session->debug = cfg->debug; 1873 session->mtu = cfg->mtu; 1874 session->mru = cfg->mru; 1875 session->send_seq = cfg->send_seq; 1876 session->recv_seq = cfg->recv_seq; 1877 session->lns_mode = cfg->lns_mode; 1878 session->reorder_timeout = cfg->reorder_timeout; 1879 session->offset = cfg->offset; 1880 session->l2specific_type = cfg->l2specific_type; 1881 session->l2specific_len = cfg->l2specific_len; 1882 session->cookie_len = cfg->cookie_len; 1883 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); 1884 session->peer_cookie_len = cfg->peer_cookie_len; 1885 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); 1886 } 1887 1888 if (tunnel->version == L2TP_HDR_VER_2) 1889 session->build_header = l2tp_build_l2tpv2_header; 1890 else 1891 session->build_header = l2tp_build_l2tpv3_header; 1892 1893 l2tp_session_set_header_len(session, tunnel->version); 1894 1895 err = l2tp_session_add_to_tunnel(tunnel, session); 1896 if (err) { 1897 kfree(session); 1898 1899 return ERR_PTR(err); 1900 } 1901 1902 /* Bump the reference count. The session context is deleted 1903 * only when this drops to zero. 1904 */ 1905 l2tp_session_inc_refcount(session); 1906 l2tp_tunnel_inc_refcount(tunnel); 1907 1908 /* Ensure tunnel socket isn't deleted */ 1909 sock_hold(tunnel->sock); 1910 1911 /* Ignore management session in session count value */ 1912 if (session->session_id != 0) 1913 atomic_inc(&l2tp_session_count); 1914 1915 return session; 1916 } 1917 1918 return ERR_PTR(-ENOMEM); 1919 } 1920 EXPORT_SYMBOL_GPL(l2tp_session_create); 1921 1922 /***************************************************************************** 1923 * Init and cleanup 1924 *****************************************************************************/ 1925 1926 static __net_init int l2tp_init_net(struct net *net) 1927 { 1928 struct l2tp_net *pn = net_generic(net, l2tp_net_id); 1929 int hash; 1930 1931 INIT_LIST_HEAD(&pn->l2tp_tunnel_list); 1932 spin_lock_init(&pn->l2tp_tunnel_list_lock); 1933 1934 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) 1935 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]); 1936 1937 spin_lock_init(&pn->l2tp_session_hlist_lock); 1938 1939 return 0; 1940 } 1941 1942 static __net_exit void l2tp_exit_net(struct net *net) 1943 { 1944 struct l2tp_net *pn = l2tp_pernet(net); 1945 struct l2tp_tunnel *tunnel = NULL; 1946 1947 rcu_read_lock_bh(); 1948 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 1949 (void)l2tp_tunnel_delete(tunnel); 1950 } 1951 rcu_read_unlock_bh(); 1952 1953 flush_workqueue(l2tp_wq); 1954 rcu_barrier(); 1955 } 1956 1957 static struct pernet_operations l2tp_net_ops = { 1958 .init = l2tp_init_net, 1959 .exit = l2tp_exit_net, 1960 .id = &l2tp_net_id, 1961 .size = sizeof(struct l2tp_net), 1962 }; 1963 1964 static int __init l2tp_init(void) 1965 { 1966 int rc = 0; 1967 1968 rc = register_pernet_device(&l2tp_net_ops); 1969 if (rc) 1970 goto out; 1971 1972 l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0); 1973 if (!l2tp_wq) { 1974 pr_err("alloc_workqueue failed\n"); 1975 unregister_pernet_device(&l2tp_net_ops); 1976 rc = -ENOMEM; 1977 goto out; 1978 } 1979 1980 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION); 1981 1982 out: 1983 return rc; 1984 } 1985 1986 static void __exit l2tp_exit(void) 1987 { 1988 unregister_pernet_device(&l2tp_net_ops); 1989 if (l2tp_wq) { 1990 destroy_workqueue(l2tp_wq); 1991 l2tp_wq = NULL; 1992 } 1993 } 1994 1995 module_init(l2tp_init); 1996 module_exit(l2tp_exit); 1997 1998 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 1999 MODULE_DESCRIPTION("L2TP core"); 2000 MODULE_LICENSE("GPL"); 2001 MODULE_VERSION(L2TP_DRV_VERSION); 2002 2003